The field of the invention is in the spark gap switch art.
Spark gap switches are well known having been used in radar equipment for many years as T-R (Transmit-Receive) switches, and more recently in pulsed laser systems. The spark gap switch as referred to herein, and as generally referred to, is used only to initiate energy flow to a load from an electrical energy storage device, such as a capacitor bank or a pulse forming network. The average power is frequently in the multimegawatt range. The energy flows until most or all of the energy stored passes the gap. At this crucial time, the cessation of the passage of energy, it is desired to reapply energy to the energy storage device. However, energy cannot be immediately reapplied with the resultant voltage build-up across the gap without the gap rebreaking down or the gap by still having a relatively low resistance across its electrodes is prohibitive or at least detrimental to a voltage build-up. The gap must be cleared of hot gasses, plasmas, and other discharge products before the voltage can be started on its building back up to discharge potential. This time that must be allowed for the switch to recover its dielectric strength; i.e., regain open circuit characteristics, is commonly called the grace period of the switch. It is a particular object of this invention to provide a novel gap structure that will shorten the grace period of spark gap switches.
Some prior art high power spark gap switches have used an air flow to remove the discharge products generated by the conduction current and clear the gap. A recent publication, of unlimited distribution, entitled "High Power Spark Gap Switch Development", published by the Air Force Aero Propulsion Laboratory, Air Force Systems Command, Wright-Patterson Air Force Base, Ohio 45433 as technical report AFAPL-TR-75-41, discloses current state of the art spark gap switches using a flow of air to clear the gap after a conduction period.
The spark gap switches using a flow of air to clear the switch after cessation of the current pulse are not to be confused with gas-blast circuit breakers. These latter devices are also well known particularly in the high power electrical switch-gear field. In them, the flow of current that is continuing in the gap formed by opening the switch is interrupted by the air flow. Many electrical utility company switches are of this type. Generally, the spark gap switch is not a circuit breaker. To further aid in distinguishing these two at first seemingly allied devices, but actually entirely different in function and operation, reference is made to the following publications. A. J. Shrapnel and D. J. Siddons, "A Model for a Convection Dominated Arc", Second International Conference on Gas Discharge, London, Engl, Sept. 1972, IEE Conference Publication No. 90, pp 317-319; and Horst Kopplin et al, "Study of the Effects of Gas Flow in the Performance of Gas-Blast Circuit Breakers", Proceedings of the IEEE, Vol, 59, No. 4, April 1971, pp 518-524.